Versions prior to 18.9-cert12 and 20.7-cert2. How to Secure Your System
At its core, CVE-2024-42491 is a critical flaw related to how Asterisk handles Session Initiation Protocol (SIP) requests. Specifically, if the res_resolver_unbound module is loaded and the system attempts to send a request to a URI with a host portion starting with .1 or [.1] , the system can suffer a segmentation fault (SEGV) and crash. The Technical "Why"
The system attempts to access a pointer that it expects to be valid but is actually NULL.
The vulnerability stems from two primary software weaknesses: